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Area forecast discussion 
National Weather Service Caribou ME
1259 PM EST Thursday Jan 29 2015

Synopsis...
high pressure crests over the region this morning and then
moves east. Low pressure approaches from the west tonight and
re-develops in the Gulf of Maine Friday. The low will then slowly
move into the Canadian Maritimes Saturday. High pressure builds
toward the region from the west Sunday into Monday.

&&

Near term /through tonight/...
update...
no significant changes. With high pressure in control
today...the focus remains on the storm system for Friday and
Saturday. While the Winter Storm Warning is in effect over a long
period of time...it should be noted that different parts of the
forecast area will see the heavier snow amounts at different
times. The most significant snow on Friday afternoon will be with
the inverted trough on the far western edge of the forecast area.
This will start affecting Bangor in the afternoon. On Friday
evening...the action shifts to Bangor and down east as the storm
intensifies. Later in the night into Saturday...the trowal moves
northward and the northeastern portion of the forecast area gets
its heaviest snow of the event.

Previous discussion...
high pressure covers the eastern U.S. Seaboard this morning and will
move east into the Atlantic today. Low pressure moving through the
Midwest and western Great Lakes will move into the eastern Great
Lakes this evening and into western New England tonight with the
energy to Transfer to the southern New England coast by 12z Friday.

Today will start sunny and cold across northern and eastern Maine.
High clouds will begin to increase from the west during the
afternoon. Shallow inversions will break and allow for a large
diurnal range in temperatures with many areas to rebound 30-40
degrees from the early morning lows. By afternoon expect just
about all of the County Warning Area to be at or above 20f. Temperatures down east will get well
into the 20s this afternoon.

Clouds will thicken up and gradually lower tonight. Across the
western zones low temperatures will likely be recorded early
(00-02z). There will be more of an opportunity for temperatures to drop
in the east where lows will mostly be observed between 04-06z.
Temperatures in all areas will slowly rise after 06z. The arrival
of the snow looks to be a few hours slower than it did last night.
Snow should begin across far western Maine after midnight and will
likely not reach the New Brunswick border until close to daybreak.
&&

Short term /Friday through Saturday/...
winter storm watches have been upgraded to warning for the entire
forecast area as a slow-moving system will bring widespread snows of
6 to 12 inches to the region.

A clipper-type low will cross into northern New York and New England
Friday and move off the southern New England coast by Friday
evening. The low will deepen as it slowly migrates toward Nova
Scotia with its upper trough cutting off and becoming negatively
tilted. Moisture will stream northward out ahead of the low,
resulting in a swath of snow. This snow will move into western
sections of our forecast area early Friday morning and slowly spread
eastward through the day. The snow will intensify through the
afternoon into the evening hours, especially in southern portions of
our forecast area as an inverted trough develops, resulting in an
area of strong moisture convergence and lift. Temperatures are a bit
tricky as they will top out in the lower to middle 30s over coastal
areas. While a bit of rain/snow mix can't be ruled out, expect the
snowfall rates in the heavier bands to be enough to overcome
marginal temperatures and allow for additional snow accumulation.
As the surface low spins into Nova Scotia, the inverted trough and
its forcing will pinwheel northward into eastern Maine. Snowfall
rates along this deformation band could be heavy at times owing to
high snow-liquid ratios. The low will slowly push eastward on
Saturday, allowing the snow to gradually come to an end from west to
east during the afternoon.

The other concern with this system will be gusty north winds that
will develop around the backside of the retreating low Saturday and
Saturday night. Given that the snow that falls Friday into Saturday
morning will be light and fluffy in nature, expect there will be a
areas of blowing and drifting snow Saturday and Saturday night.
These north winds will also usher in a much colder airmass with
temperatures likely falling through Saturday afternoon.
&&

Long term /Saturday night through Wednesday/...
any lingering snow showers will quickly come to an end Saturday
night as low pressure moves into the Canadian Maritimes. Bitterly
cold Arctic high pressure will build across New England Sunday
into Monday. Much of the area will struggle to get into the single
digits through Tuesday, with northern areas likely not getting to
zero on Monday. Overnight lows will be -10 to -20 in the north and
-5 to -15 south. This high will keep another strong low pressure
system shunted to our south Monday into Tuesday, though model
trends will have to be watched closely for any changes in track.
There could be another chance of precipitation on Wednesday as an
upper shortwave and its surface low trek across southern Quebec.
This would help to bring temperatures back closer to normal on
Wednesday.
&&

Aviation /18z Thursday through Tuesday/...
near term: VFR today into tonight. Conditions will lower to MVFR
by 12z Friday as -sn spreads in from the west.

Short term: IFR conditions are likely to prevail Friday through
Saturday morning, with LIFR possible at times in heavy snow. The
snow will wind down from west to east Saturday afternoon, but IFR
will still be possible as winds of 15 to 25 knots will result in
areas of blowing snow through Saturday night. Conditions will
improve to VFR on Sunday as high pressure builds across the
region.
&&

Marine...
near term: the wind and seas will be below Small Craft Advisory
levels through tonight.

Short term: gale headlines will likely be needed on Saturday as
winds turn to the north and increase to 30 to 40 knots in response to
low pressure crossing the Gulf of Maine and moving into Nova
Scotia. A period of small craft winds are possible Friday night,
but given that this is still a bit far out at this point, have
opted to allow later shifts to take another look and issue
headlines at a later point.
&&

Car watches/warnings/advisories...
ME...Winter Storm Warning from 7 am Friday to 7 PM EST Saturday for
mez002-005-006-011-017-030-032.
Winter Storm Warning from 4 am Friday to 1 PM EST Saturday for
mez001-003-004-010-015-016-029-031.
Marine...none.
&&

$$

Near term...cb/mcw
short term...Hastings
long term...Hastings
aviation...cb/mcw/Hastings
marine...cb/mcw/Hastings

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